Q.
I'm looking for research information on the effect of computer games, phosphorous lights on children who play late in the evening, and if it relates to sleep/mood problems. Do you know of any sources?

A.
There have been several studies of computer games, video games, etc. though I am not aware of any that looked specifically at the issue of sleep and the effects of bright light from the monitor screen. Emes (Can J Psychiatry 1997 May;42(4):409-14) reviewed this literature and found that playing video games is associated with a variety of physical effects, including increased metabolic and heart rate, seizures, and tendinitis.

Aggressive behavior may result from playing video games, especially among younger children. However, there was no direct relationship between psychopathology or academic performance and playing video games. Griffiths & Dancaster (Addict Behav 1995 Jul-Aug;20(4):543-8) examined the effect of computer games on different personality types. It was hypothesized that, during computer-game play, Type A and Type B subjects would have significantly higher heart rates as compared with baseline levels and that Type A subjects would experience a significantly greater increase in arousal when playing a computer game than Type B subjects.

These hypotheses were both supported. Based on what we know about bright light's ability to re-set the sleep/wake cycle, it does seem plausible that late-night viewing of video/computer games could have effects on sleep in children, but one would have to control for other factors (such as inherent level of arousal) that might prompt the child to be up late in the first place.